Radial bearing assemblies are utilized in many machine and tool applications to reduce rotational friction and to radial support loads. Such radial assemblies are often employed in downhole drilling motors that are commonly used for drilling boreholes in the earth for oil and gas exploration. Some radial bearing assemblies employ a pair of opposing support members each having an opposing, groove or bearing race. A plurality of supporting bearing balls is positioned in the opposing races between the support members. As one support member rotates about the other upon the bearing balls, the bearing loads are transferred to the balls and the balls rotate in the races to reduce rolling resistance and friction between the opposing support members. The bearing balls are made of a variety of materials including an assortment of steels, ceramics, or hybrids of steel and ceramics. Other radial bearing assemblies employ elongated rollers in place of the bearing balls.
Still other radial bearing assemblies employ the use of flat hard discs or plates know as inserts to line the surface of opposing support members. The hard smooth surface of the inserts serve to reduce resistance and friction between the opposing support members as these support members rotate with respect to each other. Such bearing inserts are typically made of a hard carbide such as tungsten carbide, titanium carbide, silicon carbide, diamond silicon carbide composites, polycrystalline cubic boron nitride, or polycrystalline diamond, provide high strength, wear resistance and low friction between rotating support members.
When radial bearing assemblies are constructed with such bearing inserts, each individual insert is placed in a bearing hole or aperture on the surface of the support members and attached by brazing or spot welding the insert in place on the support member or to a corresponding bearing ring positioned adjacent to the support member. A bearing hole or aperture is required for attaching the disc to the bearing surface because of the difficulties encountered when welding a flat disc to the round bearing surface. Further, the machining of individual holes or apertures for the inserts and then spot welding or brazing each individual insert in place in its aperture is time consuming and expensive. Consequently a need exists to facilitate the fabrication of radial bearings that utilize such disc inserts.